In a silver halide color photographic element or material, a color image is formed when the element is given an imagewise exposure to light and then subjected to a color development process. In the color development process silver halide is reduced to silver as a function of exposure by a color developing agent, which is oxidized and then reacts with coupler to form dye. In most color photographic elements the coupler or couplers are coated in the element in the form of small dispersion droplets. Many photographic elements or materials contain, in addition to imaging couplers, image-modifying couplers that release a photographically useful group from the coupling site upon reaction with oxidized color developer. Couplers that release a silver development inhibitor from the coupling-off position, so-called DIR couplers, are one type of image-modifying coupler commonly utilized in color photographic elements.
Many photographic materials, and especially color negative films, contain DIR (Development Inhibitor Releasing) couplers. In addition to forming imaging dye, DIR couplers, release inhibitors that can restrain silver development in the layer in which inhibitor release occurs as well as in other layers of a multilayer color photographic material. DIR couplers can help control gamma or contrast, can enhance sharpness or acutance, can reduce granularity, and can provide color correction via interlayer interimage effects.
Purine-releasing DIR couplers are generically disclosed in Japanese Patent application JP04/278942 A and in U.S. Pat. No. Re. 29,397 and in copending, commonly-assigned U.S. patent application Ser. No. 08/824,223 filed Mar. 25, 1997. However, neither the malonalilide substituted DIR couplers of the present invention nor their advantages are specifically disclosed in these references.